1. Field of the Invention
The present invention relates to noise removal systems. More particularly, the present invention relates to a method and system that can remove noise created by bias electric power (MIC_Bias) or by performing Time Division Multiple Access (TDMA) communication in a mobile device.
2. Description of the Related Art
With recent developments in technology and increased demand for various functions, mobile devices have been equipped with a variety of additional functions. The mobile devices can play back files, such as audio or video files for music or language learning, stored therein, so that a user can listen to or view corresponding audio or video. The mobile devices can also photograph pictures or record video via the camera function. They can also receive broadcast data from broadcast stations and reproduce them so that users can view broadcasts. The mobile devices can also provide an Internet function and transmit/receive Short Message Service (SMS) or Multimedia Message Service (MMS) messages.
More particularly, the mobile devices can play back various types of audio files stored therein and output audio sounds through a speaker, via an audio file playback function. Mobile device users frequently wear earphones to hear the audio sounds and to avoid disturbing others around them.
The mobile devices are equipped with an interface that is connected with a plug of headsets. The headsets are, usually, four-pole headsets with a microphone. When mobile devices are connected with the four-pole headsets, they may be subject to noise created by bias electric power (MIC_Bias) or by the use of Time Division Multiple Access (TDMA) communication. Such noise flows into an audio input-output terminal via circuitry on a Printed Circuit Board (PCB) of the mobile devices, thereby deteriorating the quality of output audio sounds.
The interface may allow the connection of various types of cables for accessories, such as audio cables, and the like. In this case, mobile devices require a circuitry to identify types of external devices connected thereto. In the mobile devices according to the related art, noise flows into the audio input-output terminal via an accessory identifying circuitry, thereby deteriorating the quality of audio sounds output from mobile devices.